Human Papilloma Virus Vaccination and Concerns

HUMAN PAPILLOMA VIRUS Vaccination and Concerns Dr.T.V.Rao MD

Human papillomavirusHuman papillomavirus (HPV) is a member of thepapillomavirus family of viruses that is capable of infectinghumans. Like all papillomaviruses, HPVs establish productiveinfections only in the stratified epithelium of the skin ormucous membranes. While the majority of the nearly 200known types of HPV cause no symptoms in most people,some types can cause warts (verrucae), while others can – ina minority of cases – lead to cancers of the cervix, vulva,vagina, and anus in women or cancers of the anus and penisin men.

Sexual Contact mainly spread the InfectionMore than 30 to 40 types of HPV are typicallytransmitted through sexual contact and infect theanogenital region. Some sexually transmitted HPVtypes may cause genital warts. Persistent infectionwith "high-risk" HPV types—different from the onesthat cause skin warts—may progress to precancerouslesions and invasive cancer. HPV infection is a cause ofnearly all cases of cervical cancer however, mostinfections with these types do not cause disease.

HPV 16 and 18 are High risk factorsHPV types 6 and 11 are typically labeled as low riskbecause infection with these types has lowoncogenic potential and usually results in theformation of condylomata and low-gradeprecancerous lesions. HPV types 16 and 18have emerged as the high-risk types of HPVbecause they are responsible for most high-gradeintraepithelial lesions that may progress tocarcinomas, particularly those in the anogenitaland/or mucosal category.

The percentages of cancers caused by oncogenic HPV are as followCervical cancer 100%Anal cancer - 90%Vulvar cancer - 40%Vaginal cancer - 40%Oropharyngeal cancer- 12%Oral cancer – 3%

The Incidence Differs in Developing WorldIn many lesser-developedcountries, cervical cancer is themost common cancer amongwomen because of the lack ofeffective screening programs thatmonitor cervical cytology by Papsmear.3 However, a single round ofHPV screening has beendemonstrated to be far superior toconventional cytology in reducingthe incidence of cervical cancermorbidity and mortality.4

Can Cause Cancers Several Types of CancersHPV infections can persistfor many years. Persistentinfections with high-riskHPVs are the primarycause of cervical cancer.HPV infections also causesome cancers of the anus,vulva, vagina, penis, andoropharynx

What is the association between HPV infection and cancer? Persistent HPV infections are now recognized as the cause of essentially all cervical cancers. It was estimated that, in 2010, about 12,000 women in the United States would be diagnosed with this type of cancer and more than 4,000 would die from it. Cervical cancer is diagnosed in nearly half a million women each year worldwide, claiming a quarter of a million lives annually.

Multiple Sex Partners a Risk FactorHaving many sexual partners is a riskfactor for HPV infection.Nevertheless, most HPV infectionsgo away on their own withoutcausing any type of abnormality.However, even among women whodevelop abnormal cervical cellchanges because of persistentinfection with high-risk HPV types,the chances of developing cervicalcancer are small, even if theabnormal cells are not treated.

Human Papilloma VirusSexually Transmitted Virus which can lead to cervical dysplasia (cancer). Found in 99.7% of all cervical cancers Types {16,18,31,45} account for 75% of cervical cancer

Human Papilloma Virus80% of the sexually active adult population will contract HPV U.S. spent over $1.6 billion in treating symptoms of HPV U.S. estimates 13,000 cases of cervical2004 cancer 2005 $5-6 billion spent on screening tests such as More than 5,000 will die pap smears. from cervical cancer

Sexually Active Ages Given this concept of sexual activity the age ranges for each model are: HPV 15-30 15 300 20 40 Age (years)

Risk of TransmissionThe risk of transmission is based on two factors: The risk of transmission in one sexual encounter The average number of sexual encounters with one partner

Pathophysiology of HPV InfectionLaboratory research has indicated thatHPVs produce proteins known as E5,E6, and E7. These proteins interferewith the cell functions that normallyprevent excessive growth. Forexample, HPV E6 interferes with thehuman protein p53, which acts to keeptumors from growing. A betterunderstanding of how these proteinsinteract may help researchers developways to interrupt the process by whichHPV infection can lead to the growthof abnormal cells

Relative Risk of TransmissionHPV : Male-to-Female 80% Female-to-Male 70%

How are HPV infections detected?Cervical cells can be tested to identify high-risk types of HPVthat may be present. HPV DNA tests look for viral DNA frommultiple high-risk HPV types and can detect the presence of aviral infection before any cell abnormalities become visible.The FDA has approved HPV DNA tests for follow-up testing ofwomen with equivocal cell abnormalities on a Pap test (ascreening test to detect cervical cell changes). HPV DNA testsare also approved for general cervical cancer screening ofwomen over the age of 30 when done together with a Paptest. There are currently no approved tests to detectHPV infections in men.

FDA Approves Vaccine for HPVThe U.S. Food and Drug Administration (FDA) has approved twovaccines to prevent HPV infection: Gardasil® and Cervarix®. Bothvaccines are highly effective in preventing persistent infections withHPV types 16 and 18, two high-risk HPVs that cause most (70percent) cervical cancers. Gardasil also prevents infection with HPVtypes 6 and 11, which cause virtually all (90 percent) genital warts . Inaddition, there is some initial evidence that Cervarix provides partialprotection against a few other HPV types that can cause cancer, butfurther evaluation is required before the magnitude and impact of thiseffect is understood.

Two Vaccines are Licensed for Human Use Both Gardasil and Cervarix are based on technology developed in part by National Cancer Institute (NCI) scientists. NCI, a component of the National Institutes of Health, licensed the technology to two pharmaceutical companies— Merck and GSK—to develop HPV vaccines for widespread distribution.

Gardasil vaccineThe Gardasil vaccine, which is producedby Merck & Co., Inc. (Merck), is called aquadrivalent vaccine because it protectsagainst four HPV types: 6, 11, 16, and18. Gardasil is given through a series ofthree injections into muscle tissue over a6-month period. The FDA has approvedGardasil for use in females for theprevention of cervical cancer, and somevulvar and vaginal cancers, caused byHPV types 16 and 18 and for use in malesand females for the prevention of genitalwarts caused by HPV types 6 and 11. Thevaccine is approved for these uses infemales and males ages 9 to 26.

Cervarix Vaccine Cervarix is produced by GlaxoSmithKline (GSK). It is called a bivalent vaccine because it targets two HPV types: 16 and 18. This vaccine is also given in three doses over a 6-month period. The FDA has approved Cervarix for use in females ages 10 to 25 for the prevention of cervical cancer caused by HPV types 16 and 18.

The Vaccines are Effective in Targeted HPV types Gardasil and Cervarix are highly effective in preventing infection with the types of HPV they target. Studies have shown that both Gardasil and Cervarix prevent nearly 100 percent of the precancerous cervical cell changes caused by the types of HPV targeted by the vaccine for up to 4 years after vaccination among women who were not infected at the time of vaccination

HPV is Totally Not Protective ?Neither of these HPV vaccineshas been proven to providecomplete protection againstpersistent infection with otherHPV types, although someinitial results suggest that bothvaccines might provide partialprotection against a fewadditional HPV types that cancause cervical cancer.

Vaccine is Not Totally Protective on all types of HPV Overall, therefore, about 30 percent of cervical cancers will not be prevented by these vaccines. Also, in the case of Gardasil, 10 percent of genital warts will not be prevented by the vaccine. Neither vaccine prevents other sexually transmitted diseases, and they do not treat HPV infection or cervical cancer.

A Regular Check up for Detection of Cancer Cervix essential even in ImmunizedBecause the vaccines donot protect against allHPV infections that causecervical cancer, it isimportant for vaccinatedwomen to continue toundergo cervical cancerscreening asrecommended for womenwho have not beenvaccinated.

How long do the vaccines protect against infection?The duration of immunity is not yetknown. Research is being conductedto find out how long protection willlast. Phase III clinical trials haveshown that Gardasil and Cervarix canprovide protection against HPV16 for4 years. Smaller studies havesuggested that protection is likely tolast for longer than 4 years, but it isnot known if protection conferredthrough vaccination will be lifelong

Will booster vaccinations be needed? Studies are under way to determine whether booster vaccinations (supplementary doses of a vaccine, usually smaller than the initial dose or doses, that are given to maintain immunity) are necessary.

Who should get these vaccines?Both Gardasil and Cervarix areproven to be effective only if givenbefore infection with HPV, so it isrecommended that they be givenbefore an individual is sexuallyactive. The FDAs licensing decisionincludes information about the ageand sex for recipients of the vaccine.The FDA approved Gardasil for use infemales ages 9 to 26 and approvedCervarix for use in females ages 10 to25.

Vaccination in Males Data from Merck show high efficacy of Gardasil in males for preventing genital warts associated with HPV6 and HPV11, the two HPV types that cause most genital warts. The FDA approved Gardasil for use in males ages 9 to 26 to prevent genital warts caused by HPV6 and HPV11.

HPV Total Sexually Active PopulationSusceptible Vaccinated VaccinatedInfectious Infectious Note: A constant population is maintained. Every year/update in the Recovered model a proportion of the population Enters or ages-in as susceptibles Leaves or ages-out

Concerns on HPV Vaccination Reports of adverse events after administration of the human papillomavirus (HPV) vaccine (Gardasil, Merck) have been making headlines, and questions over the safety of the vaccine have been raised by consumers, parents, healthcare professionals, and others, notes a recent joint statement from the US Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA). But having analyzed the available data, the agencies offer reassurance.

HPV safety is EvaluatedGardasil is 1 of the "most heavilystudied and intensively monitoredvaccines," commented JohnIskander, MD, acting directorof the Immunization SafetyOffice at the CDC in Atlanta,Georgia. So far the available datasuggest that it is safe, he said in aninterview, although he added that"there are no medical products,including vaccines, that arecompletely safe and effective."

Adverse-Event Reports on Watchdog Web SitesThe actual reports collected byVAERS have been madeavailable on the Web site of thewatchdog organization JudicialWatch, which obtained the recordsfrom the FDA under the Freedom ofInformation Act. A compact disccontaining 8864 records was sentby the FDA on June 10, 2008.

PAP Smear is Still Important for timely Diagnosis of Caner Cervix Regardless of whether a woman chooses to be vaccinated or not, the take-home message is to start and continue Pap screening throughout your life," Dr. Harper

Is there a totally Safe and Highly Effective VaccineThe question remainsunanswered as there is noVaccine which is totally safeand Highly effective toprevent or cure a Diseases.The facts should be learntwith continuous observationand well communicatedKnowledge through variouspeer reviewed Information

The Programme is Created by Dr.T.V.Rao MD for ‘ e’ Learning resources for Medical andParamedical Professionals in Developing World Email doctortvrao@gmail.com

Human Papilloma Virus Vaccination and Concerns

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